Application of light or optical energy to a tissue surface can be used in various medical procedures and treatments. For example, light can be applied to a biological tissue surface in order to facilitate healing of a wound site, to remove a stenosis in a blood vessel, for photodynamic therapy (PDT) of tissue, and for photochemical tissue bonding, where light-activated substances can promote adhesion or joining of adjacent tissue surfaces. It has also been observed that application of an appropriate dye to a tissue surface, followed by irradiation with light of an appropriate wavelength, can stabilize the tissue surface and prevent or inhibit scarring and other undesirable healing effects.
In such optical treatments, it may be desirable to apply light energy to an internal tissue surface, e.g., a natural or surgically-formed body cavity or lumen. In a further example, it has been observed that treating a tissue wound surface with an appropriate dye and light (or light alone) intra-surgically can preserve normal tissue architecture, reduce post-surgical inflammation, and reduce or prevent the development of pathogenic collagen bundles (a fibrotic response) following surgery. Such treatment may improve wound healing and lead to reduced adhesion formation, scarring and wound contracture.
Light-based tissue therapy can be used, e.g., to reduce the likelihood or extent of capsular contracture following augmentation mammoplasty with prosthetic implants. Within a decade of surgery, about 50% of patients develop capsular contracture which may lead to significant morbidity and need for reoperation. Currently, there is no preventative treatment available and the recurrence rate remains high, even after capsulectomy.
Neocollagen formation and cross-linking are part of the typical human wound healing response. In capsular contracture, these processes go awry, resulting in dense, linear bundles of collagen fibers that surround the affected implant. These fibers form a firm capsule that subsequently contracts and tightens. Direct pressure from a maturing capsule may deform or rupture the implant, in addition to distorting the overlying skin and soft tissue. The condition may be painful and debilitating as well as aesthetically inferior. Application of light therapy to the interior tissue surface of the implant cavity may reduce or prevent the initial incidence of capsular contracture as well as its recurrence.
Uniformity of light fluence can be important for effective and reliable phototreatment of a tissue surface. However, such uniformity can be difficult to achieve in body cavities or lumens, particularly when they may have an irregular shape. To address this need, various devices have been developed to introduce a light emitter into a body cavity to provide substantially uniform illumination of the surrounding tissue. Such devices typically include a balloon or other flexible membrane that can be introduced into the body cavity, with a light emitter provided within the balloon.
For example, U.S. Pat. No. 5,527,308 of Anderson et al. describes an illuminator device that includes a laser fiber disposed within an optionally expandable optical radiator, wherein the radiator material has particular optical properties (relative diffusivity and reflectivity values) to facilitate uniform irradiation of the surrounding tissue surface. Generally similar illumination devices that can be deployed within a body cavity are described, e.g., in International Patent Publication No. WO 2010/062769 of Gertz et al., and in U.S. Pat. No. 6,364,874 of Bays el al. The uniformity of light fluence on the tissue produced by such devices can be affected by deformation of the membrane or balloon material, which can exhibit nonuniform local variations in thickness when the balloon is expanded or stretched to fill the body cavity or lumen.
Therefore, an illumination apparatus or kit that can provide substantially uniform illumination to the inner surface of a body cavity, which is substantially unaffected by deformation of a membrane or film contacting the inner surface, would be highly desirable.